The Girodisc system is a direct replacement for the OE disc. No modifications are necessary. The disc will bolt directly to the car and work with OE calipers perfectly. By upgrading your brakes with lightweight high performance replacements as opposed to a big brake kit, your factory bias is maintained as well as your ABS efficiency. The Girodisc front rotors are approx 17.4lbs vs. 23.5lbs for the stock units. This reduction in rotational and unsprung weight allows for quicker acceleration and suspension response. The central hat section of the disc is made from 6061-T6 aircraft specification aluminum. The disc is made from cast iron to the same specification and material as used by professional racing organizations.